"The drugs were hidden in the lower engine compartments of the vessel and around the keel area," she said.

"Officers from all of the agencies spent some number of hours chiselling through the concrete and ultimately the rocks to reach the concealed drugs."

Authorities say the yacht was up for sale when the bust was made.

If it made it to Australian shores, the cocaine could have been used in more than 750,000 deals on Australian streets.

"We are well aware that international criminals see Australia as a lucrative market for their drugs, but we will continue to work closely with our partners to identify syndicates such as these, and ensure their shipments never make it to the streets of Australia," Assistant Commissioner Jabbour said.